Means for determining the acceleration or deceleration of moving bodies



' R RUB S REF ERENCE SEARC MEANS FOR NING THE: ACCELERATION ORDECELERATION OF MOVING BODIES X 3a eT :20 33A! Maren 13, 1mm. n. L. may.

Filed NOV. 11, 1936 1 fiz orrzez 5 Patented Mar. 19, 1940 PATENT OFFICEMEANS FOR DETERMINING THE ACCELERA- TION OR DECELERATION OF MOVINGBODIES Rosser L. Wilson, Mahwah, N. J., assignor to The American BrakeShoe and. Foundry Company, New York, N. Y., a corporation of Dela-Application November 11, 1936, Serial No.-110,411

2 Claims.

This invention relates to a means for determining the acceleration ordeceleration of moving bodies when the velocity thereoi' is affected.

Acceleration may be defined as the rate of increase of velocity of amoving body in unit time. It is expressed, for example, in re olutionsper minute per minute or in revolutions per second per second or in feetper second per second. Deceleration is the opposite, that is to say, itmay be defined.- as the rate of increase of velocity of a moving body inunit time. It is expressed similarly to acceleration. r

The primary object of my invention is to de termine directly theacceleration or deceleration of a moving body whenthe velocity thereofis affected and. an ancillary object is to either indicate accelerationor deceleration on an instrument which may be calibrated, it desired, toread acceleration or deceleration directly or to utilize the determinedrate-of change in the velocity to control the' operation of selectedapparatus.

Another object is to determine the acceleration or deceleration ofmoving bodies at all speeds of movement thereof and a further object isto enable use or the same mechanism to determine the acceleration ordeceleration of moving bodies at all speeds of movement of the bodies.

In testing various'kinds of devices which effect the velocity of movingbodies, among which may be cited brake elements for deceleratingrotating bodies, it is desirable to compare different devices wherebythe relative efliciencies thereof may be determined and it is essentialthat this be performed accuratelyso that reliable result will beobtained.v

It is therefore stillanother object of my ins vention to accuratelydetermine the acceleration or deceleration ofa moving body when theveloc-.

ity thereof is affected in order that reliable comparisons may be madebetween difierent devices affecting the velocity of the body, and afurther object is to effect this in a sensitive manner so that slightvariations in the rate of change of velocity may be determined and closecomparison of devices may be made, and objects ancillary to thisare toeliminate as far as possible relative movement in the actuating means ofthe device employed to determine the acceleration or deceleration and byreason of this elimination of relative movement to insure accuracy insuch determination.

A further object is to determine acceleration or deceleration bymeasuring the resultant force exerted by the inertia of a known masswhen the velocity of a moving body is affected.

A still further object is to effect a flow of current in an electricalcircuit proportionate to the rate of variation oi. the velocity of amoving body and to measure such current flow in the circuit and therebydetermine the acceleration or deceleration of the moving body.

Selected embodiments oi my invention are illustrated in the accompanyingdrawing wherein Fig. 1 is a fragmentary side elevational view of arotatable disc and wherein certain of the means responsive to the rateof variation of the velocity of a rotating body associated .with thedisc are shown in section;

Fig. 2 is a sectional detail view taken substan tially on the line 2-2on Fig. 1 and wherein electrical apparatus used with the illustrateddevices is diagrammatically illustrated; and

Fig. 3 is a view, partly in elevation and partly in section, of a form01 my invention adapted formeasuring the acceleration or deceleration ofa rectilinear-1y movable body and wherein electrical apparatus used withthe illustrated devices is diagrammatically illustrated.

Referring to the accompanying drawing and particularly to Figs. 1 and 2thereof wherein one form of my invention is illustrated, 4 indicates ashaft to which rotative movement. is imparted from asuitable source ofpower and which may be accelerated or decelerated as desired. Ananti-friction bearing 5 is mounted on this shaft and rotatably supportsa disc or flywheel 6 on the shaft. A lug 1 extends axially from one faceof the disc into a bifurcation provided bea tween the arms. 8 and 9projecting from the collar l0 fast on the shaft 4 in spaced relationwith thebearing 5.

An annular flange H projects from the outwardiy disposed face of the arm8 and one end of a sleeve I2 is screw-threaded onto the periphery ofthis flange as indicated at 13. A solenoid coil 14 is mounted on the arm8 and is enclosed in the" sleeve [2. l2 opposite that connected to thearm 8 is closed by a plate 15', on the inner side of which is a carbonpile I6 is mounted, the pile being insulated from the plate. The coil I4is wound on a I sleeve ll of insulating material and through which asectional plunger, generally indicated by I8, is freely passed. Theplunger l8 comprises sections. of unlike metals, one magnetic andv theother non-magnetic. For example, the section [9 of the plunger l8 may beof iron and the section 20 may be of brass. The free end of the sectionIQ of the plunger [8 is enlarged and is disposed to bear upon the carbonpile IS. The

The end of the sleeve into a bushing 2| of insulating material in thelug 1 whereby this end of the plunger I8 is firmly connected to the lugand the plunger is insulated from the frame of the structure.

A recess 9' is provided in the arm 9 and a. spring i is extended intothis recess to bear on the adjusting 'sciew H having a lock nut l2thereon. The spring I 0' is engaged with the adjacent end of the plungerl8 for a purpose explained presently and is insulated from the adjustingscrew H, a member of insulating material beingmounted in the recess anddisposed between the" spring and the adjusting screw;

As best shown in Fig. 2, a source of current such as a battery 22' isprovided. A conductor 23 extends frornone terminal ofthis battery to abrush 24. A conductor 25 extends from the other end of the battery 22 toone terminal of a suitable electrical instrument A such as an ammeter. Aconductor 26 extends from the other terminal of this instrument to abrush 21. The instrument may be provided with a knob K by means of whichthe scale of the instrument may be adjimted to a zero position when abalanced condition, described hereinafter, is established.

The collar [0 includes a reduced portion 28 on which a ring ofinsulating material 29 is fast.

A conductor ring 30 is fast on the periphery of the lnsulating'ring 29and the-brush 24 bears conductor 34 is connected to one end ofthewinding of the coil I4. A conductor 35 interconnects the other end ofthe winding of this coil and the carbon pile IS. The conductor 33 isalso connected to the carbon pile and the connections are such that the.pile is disposedbetween the conductors 33 and 36. The above describedvconnections are such that the carbon pile l6 and coil M are connected inseries with each other and with the instrument A and bat tery 22, therings 30 and 3| and brushes 24 and 21 affording interconnection betweenthe rotatable coil and carbon pile and the stationary battery andinstrument.

The disc 6,-lug l and plunge'r lB' are of known mass and by reason ofthe anti-friction bearing these-parts are free to float on the shaft 4but rotate with the shaft, when it is driven, by reason of the extensionof the lug 1 into the bifurcation between the arms 8 and 9. The springl0, which is insulated from the arm 9, is adjusted to exert such forceon the plunger l8 that when the disc 5 and the parts thereon and shaft 4and the parts thereon are both rotating at a given velocity, the plungerbears on the carbon pile IE to establish the resistance of the pile at apoint such that the current flow through the coil l4 sets up a magneticfield which, by its effect on the plunger, maintains the plunger in itsposition. In this way a balanced condition is established.

The device as thus far described is particularly useful for indicatingvdeceleration as, for exam- It! is so adjusted that when the shaft 4 andY 1 disc 6 are rotating together at a given velocity, the pressure ofthe plunger 18 on the carbon pile l6 establishes a balanced condition;as aforesaid. This establishes a current flow that is indicated on theinstrument but the knob K may now be grasped and the scale of theinstru- 'ment adjusted to establish a zero condition on the instrument,that is to say, to align the indicator of the instrument with zero ofthe scale. When the shaft 4 is 'decelerated, the inertia of the disc 6exerts a force on the plunger l8 erted by the coil on the plunger beingsubstantially equal to. and opposite to the inertia force of the disc onthe plunger 16 and insuring that the plunger maintains the newlyestablished pressure on the carbon pile. The amrneter A measures theincrease incurrent flow under these conditions and when anindicatinginstrument, such as that illustrated, isemployed the currentflow is registered but if a recording instrument of the kind'wellunderstood in the art is substituted for the indicating instrumentillustrated a record of the increase in current flow is produced.

Since the disc 6, lug l. and plunger 18 are of a known mass, thedeceleration may be determined from the amperage indicated or recordedby the instrument A in the manner well understood in the art.Furthermore, as is well understood, the instrument A may be calibratedto directly indicate or record the deceleration.

The form of the invention shown in Fig; 3 is adapted for determining theacceleration or deceleration of a rectilinearly moving body andespecially of a body moving horizontally in a straight line. To this enda mass such as a pendulum P or other freely movable mass is suitablysupported on the moving body B which exerts a force rearwardlyupon-acceleration of the body and forwardly upon deceleration of thebody.

A bracket 37 is mounted forwardly of the pendulum P on the body Bandanother bracket 3:8 is mounted on said body rearwardly of thependulum. A sleeve 39 is mounted on the bracket 37 to extend forwardlytherefrom and another sleeve is mounted on the bracket 38 to extendrearwardly therefrom. The sleeves 39 and 40 are similar to the sleeve l2illustrated in Fig. 1.

A coil 4| is mounted in the sleeve 39 and a carbon pile 42 is alsomounted therein and a coil 43 and a carbon pile 44 are mounted in thesleeve 40. A plunger 45 extends forwardly from the pendulum P throughthe coil 4| and is adapted to bear on the carbon pile and exert forcethereon upon deceleration of the body B. The plunger 46 extendsrearwardly from the pendulum P through the coil 33 to bear upon thecarbon pile 44 and exert force thereon upon acceleration of the body B..Both the pioneers 45 and 46 are constructed similarly to the plunger 18.

The carbon pilw 42 and 44 are maintained,

"spring l0 and adjusting screw II.

A source of current such as the battery 41 is provided. An instrument A,such as an indicating or recording ammeter, is also provided and in thisinstance the indicating element of the instrument is arranged tobe-movable in opposite directions from a median posi tion, said elementmoving to the right, as viewed in Fig. 3, to indicate or recorddeceleration of the body B andv to the left to indicate or recordacceleration of said body. The instrument A is preferably equipped witha knob K for centering the scale thereof in the same manner as that inwhich the knob'K is employed to center the scale of the instrument A.

Terminals 48 and 49, are providedon the left- .hand side of theinstrument A and'the means responsive to acceleration are connectedthereto while terminals 50' and 5! are provided on the.

right-hand side of the instrument and the means responsive todeceleration of the body B are connected thereto. one terminal of thebattery 41 and a conductor 53 interconnects the conductor 52 and theterminal 48 while a conductor 54 interconnects the conductor 52 and theterminal 58. A conductor 55 extends from the other terminal of thebattery 41.

A conductor 55 extends from the conductor 55 to the carbon pile 42.Another conductor 51 extends from-the carbon pile to one-end of thewinding of the coil 4!, the carbon pile 42 being disposed between theconductors Stand 51. A

conductor 58 connects the other end of the wind-' ing of the coil 4!with the terminal 5!. A conductor 58 leads from the conductor 55 to thecarbon pile 44 and a conductor leads from this carbon pile to one endofthe winding of'the coi1'43, the carbon pile 44 being disposed betweenthe conductors 59 and 50'. Av conductor Bl connects the other end of thewinding of the coil 43 with the terminal 45.

When the body 13 is moving at a given velocity the pendulum P bears uponthe carbon piles 42 and 44 to set up a current flow through the coils 4iand 43 that sets up magnetic fields which act on the plunger's- 45 and48 to maintain these plungers in position to so bear on the carbon pilesthat the aforesaid current flow is main-'- tained constant. When.however, the body B is accelerated, the pendulum P exerts an inertiaforce directly proportionate to the degree of acceleration of the body Bupon the carbon pile 44 to decrease the resistance thereof which efiectsa flow of current'through the coil 43 with the efiect described above inconnection with coil [4, and the movable element 01. the instrument Amoves to the left as viewed in Fig. 3 to indicate the amperage of thisincreased current flow whereupon the acceleration is determined directlyas described heretofore. -Likewise, when the body B is decelerated aninertia force is in pressed upon the carbon pile 42 whereupon the Aconductor-52 leads from tion is to be determined.

Inasmuch as inertia force is the predominant,

element of the instrument A moves to the right as viewed in Fig. 3, andas above described the deceleration may therefore be determineddirectly.

By providing a device similar to that shown in Figs. 1 and 2 and facingthis device in the direction opposite to that in which the illustrateddevice faces, acceleration may be determined. Furthermore, by reason ofthe rigid construction afforded the device is not affected bycentriiugal force even when the disc 6 is rotated at a high rate ofspeed.

Both forms or the invention have been described as being employed toindicate or record acceleration, or deceleration but it is to beunderstood that suitable. means to control operation of selectedapparatus might be substituted for the indicating or recordinginstruments. Thus, for example, control apparatus could be provided forregulating the operation of the means which efiect the acceleration ordeceleration whereby such acceleration or deceleration could becontrolled. Such an arrangement will beparticularly advantageous incontrolling brakeseflecting the deceleration oi! moving bodies so thatthe deceleration can be maintained constant within close limits, andthis arrangement might be utilized in connection with the brake systemof railway equipment whereby smooth stops of the equipment can beeffected rapidly without objectionable jerking or sliding of the wheels.

It is to be understood that while I have illustrated and described theknown mass as being movedat a velocity equal to that of the body, it isonly important that the mass be moved at a velocity proportionate tothat of the body.

One of the important advantages oi my invention is that the resistance.of the carbon pile or other variable resistance devices is affected byvery slight movements measurable, for exam-- ple, in thousandths of aninch, and therefore relative movement in the actuating devices of themeans which I employ for determining acceleration or deceleration isreduced to a minimum and is substantially eliminatedand this isaugmented by the fact that the known mass is engaged with the movingbody whose acceleration or decelerafactor in my invention fordetermining acceleration or deceleration and as this force is directlyproportionate to slight variations it is manifest that slightaccelerations or decelerations may be determined and moreover allaccelerations and sive. Hence, it will be understood that the weigh-.

ing means need not be that which has been illustrated and described forother suitable means may be employed for the purpose. Thus. ifelectrical means are employed other forms of variable resistance means,or which well known variable resistance crystals are an example, may beused and pneumatic, hydraulic or mechanical weighing means may beemployed if desired.

While I have illustrated and described selected embodiments of myinvention it is to be understood that these are capable of variation andmodification and I therefore do not wish to be limited to the precisedetails set forth but desire to avail myself oi such changes andalterations as {all within the scope or the following claims I claim;

1. In a device for measuring the acceleration or deceleration of arotatable body, a known mass including a plunger, means for rotating theknown mass at a velocity equal to the velocity of the body, anelectrical circuit includinga coil mounted on'said body and throughwhich said plunger is extended andalso including means mounted on saidbody and on which the inertia force of said mass is impressed by saidplunger when thevvelocity'of said body is ailected and op erable toinduce a current flow through said circuit proportionate to the-inertiaforce to thereby cause said coil to exert a force on said plunger equalto and opposite to said inertia force, and means in said circuit formeasuring the induced current flow.

2. In a device for measuring the acceleration or deceleration of arotatable body, aknown mass including a plunger, means for rotating theknown mass ata velocity equal to the velocity of the body, an electricalcircuit including a. coil mounted on said body and through which saidplunger is 'extended and also including means mounted on said body andon which the inertia force of said-mass is impressed by said plungerwhen the velocity oi said'body is affected and operable to induce acurrent now through said circuit proportionate to the inertia force tothereby cause said coil to exert a force on said plungersubstantially'equal to and opposite to said in- 1 ertia force,stationary means in said circuit for measuring the induced current flow,and means in said circuit for electrically connecting the stationarymeans in said circuit with the coil and means in said circuit mounted onsaid rotatable body.

ROSSER It mos. no

